long call_proc(){
    long x1 = 1;
    int x2 = 2;
    short x3 = 3;
    char x4 = 4;
    test_args(x1, &x1, x2, &x2, x3, &x3, x4, &x4);
    
    return (x1+x2) * (x3-x4);
}